“Many of the ads have not contained misleading claims, but the issue has also been addressed in a separate study by the non-profit organisation First Draft.

It looked just at every paid-for Facebook ad from the three main UK-wide parties run over the first four days of December:

for the Conservatives, it said that 88% (5,952) of the party’s most widely promoted ads either featured claims which had been flagged by independent fact-checking organisations including BBC Reality Check as not correct or not entirely correct.

The figure includes instances of the same claims being made across multiple posts. One example was that Labour would spend £1.2 trillion at a cost of £2,400 to every household, which was contained within 4,028 ads.

Those sums are significantly higher than others’ analysis of Labour’s plans.

For the Lib Dems, it said hundreds of potentially misleading ads had featured identical unlabelled graphs, with no indication of the source data, to claim it was the only party that could beat either Labour, the Conservatives or the SNP “in seats like yours”.

For Labour, it said that it could not find any misleading claims in ads run over the period. However, it noted that the party’s supporters were more likely to share unpaid-for electioneering posts than those of its rivals. It said one of these contained leader Jeremy Corbyn’s disputed claim that a Tory-negotiated trade deal with the US could cost the NHS up to £500m a week by driving up the cost of medicines